cleavage-planes

cleavage

[klee-vij]
noun
1.
the act of cleaving or splitting.
2.
the state of being cleft.
3.
the area between a woman's breasts, especially when revealed by a low-cut neckline.
4.
a critical division in opinion, beliefs, interests, etc., as leading to opposition between two groups: a growing cleavage between the Conservative and Liberal wings of the party.
5.
the tendency of crystals, certain minerals, rocks, etc., to break in preferred directions so as to yield more or less smooth surfaces (cleavage planes)
6.
Embryology. the total or partial division of the egg into smaller cells or blastomeres.
7.
Also called scission. Chemistry. the breaking down of a molecule or compound into simpler structures.

Origin:
1810–20; cleave2 + -age

Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
Cite This Source Link To cleavage-planes
Collins
World English Dictionary
cleavage (ˈkliːvɪdʒ)
 
n
1.  informal the separation between a woman's breasts, esp as revealed by a low-cut dress
2.  a division or split
3.  (of crystals) the act of splitting or the tendency to split along definite planes so as to yield smooth surfaces
4.  embryol Also called: segmentation (in animals) the repeated division of a fertilized ovum into a solid ball of cells (a morula), which later becomes hollow (a blastula)
5.  the breaking of a chemical bond in a molecule to give smaller molecules or radicals
6.  geology the natural splitting of certain rocks, or minerals such as slates, or micas along the planes of weakness

Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
Cite This Source
Etymonline
Word Origin & History

cleavage
1816, in geology, "action of splitting (rocks or gems) along natural fissures," from cleave (1). General meaning "action or state of cleaving or being cleft" is from 1867. The sense of "cleft between a woman's breasts in low-cut clothing" is first recorded 1946, when it was
defined in a "Time" magazine article as the "Johnston Office trade term for the shadowed depression dividing an actress' bosom into two distinct sections" [Aug. 5].
Online Etymology Dictionary, © 2010 Douglas Harper
Cite This Source
American Heritage
Medical Dictionary

cleavage cleav·age (klē'vĭj)
n.

  1. A series of cell divisions in the ovum immediately following fertilization. Also called segmentation.

  2. The splitting of a complex molecule into two or more simpler molecules. Also called scission.

  3. The linear clefts in the skin, indicating the general direction of the fibers in the dermis.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Cite This Source
American Heritage
Science Dictionary
cleavage   (klē'vĭj)  Pronunciation Key 
  1. Geology The breaking of certain minerals along specific planes, making smooth surfaces. These surfaces are parallel to the faces of the molecular crystals that make up the minerals. A mineral that exhibits cleavage breaks into smooth pieces with the same pattern of parallel surfaces regardless of how many times it is broken. Some minerals, like quartz, do not have a cleavage and break into uneven pieces with rough surfaces.

    1. Biology The series of mitotic cell divisions by which a single fertilized egg cell becomes a many-celled blastula. Each division produces cells half the size of the parent cell.

    2. Any of the single cell divisions in such a series.


The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
Cite This Source
American Heritage
Cultural Dictionary

cleavage definition


The process by which an animal cell divides into two daughter cells after mitosis. In an embryo, this process is repeated many times and leads to the formation of the blastula.

The American Heritage® New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
Cite This Source
Copyright © 2014 Dictionary.com, LLC. All rights reserved.
  • Please Login or Sign Up to use the Recent Searches feature